1. Field of the Invention
The invention generally relates to a bi-directional reactor and supported monoethenalamine (MEA), and more particularly to a method and system for carbon dioxide sequestration utilizing a bi-directional reactor and monoethenalamine (MEA) on a substrate.
2. Discussion of the Related Art
The atmospheric CO2 concentration has increased by almost 38% since the beginning of the industrial revolution to a current level of about 386.8 ppm. Barrie, et al., “WMO Greenhouse Gas Bulletin,” World Meteorological Organization, Nov. 24, 2010, No. 6, pp. 1-4, which is hereby incorporated by reference as if fully set forth herein. More than 30% of all anthropogenic CO2 emissions are estimated to have resulted from fossil fuel based electricity generation. “What is CCS?” IEA Greenhouse Gas R&D Programme, © 2010, printed Apr. 30, 2012, from http://www.ieaghg.org/index.php?/20091218110/what-is-css.html, 2 pages, which is hereby incorporated by reference as if fully set forth herein. These fossil fuels, including coal, oil and natural gas, will be used as major energy sources for the foreseeable future due to their low prices and abundance. However, people are concerned about the increase of CO2 concentration in the atmosphere since CO2 has been implicated as one of the main greenhouse gases leading to global climate changes. Accordingly, capture of CO2 from flue gas streams in fossil-fuel based power plants has been considered as one of the major strategies for reduction of anthropogenic CO2 emissions and thus the potential risks resulting from climate changes.
To date, all commercial CO2 capture processes have been based on liquid amine compounds. Amine solutions are basic and can chemically remove many acid gases, including CO2, from flue gas. Danckwerts, “Reaction of CO2 with ethanolamines,” Chemical Engineering Science, 1979, 34, (4), pp. 443-446, which is hereby incorporated by reference as if fully set forth herein. Among the frequently used amine compounds is monoethanolamine (MEA). Aqueous amines along with membranes have been successfully used for separation of CO2 from natural gas, however, they have not been used in fossil fuel based power plants since the overall costs associated with the current technologies are too high to be acceptable. The high costs are mainly due to the use of large concentrations of water in the aqueous amine solutions made for carbon dioxide separation. Typical amine solutions used by the natural gas industry for gas cleaning can contain as much as 70 wt % water. Abu-Zahra, et al., “CO2 capture from power plants. Part I. A parametric study of the technical-performance based on monoethanolamine,” International Journal of Greenhouse Gas Control, 2007, 1, (1), pp. 37-46; Feng, et al., “Reduction of Energy Requirement of CO2 Desorption by Adding Acid into CO2-Loaded Solvent,” Energy & Fuels, 2010, 24, pp. 213-219, each of which is hereby incorporated by reference as if fully set forth herein.
In recent years, people are increasingly interested in using solid sorbents synthesized with amines and solid supports or grafting materials for CO2 capture in power plants. Different support materials have been used for immobilization of amines. Tanaka, “Comparison of thermal-properties and kinetics of decompositions of NAHCO3 and KHCO3,” Journal of Thermal Analysis, 1987, 32, (2), pp. 521-526; Glasscock, et al., “CO2 absorption desorption in mixtures of methyldiethanolamine with monoethanolamine or diethanolamine,” Chemical Engineering Science, 1991, 46, (11), pp. 2829-2845; Hagewiesche, et al., “Absorption of carbon-dioxide into aqueous blends of monoethanolamine and n-methyldiethanolamine,” Chemical Engineering Science, 1995, 50, (7), pp. 1071-1079, each of which is hereby incorporated by reference as if fully set forth herein. Compared to aqueous amines, solid sorbents have several advantages when used for separation of CO2 from flue gases in power plants. Mandal, et al., “Removal of carbon dioxide by absorption in mixed amines: modelling of absorption in aqueous MDEA/MEA and AMP/MEA solutions,” Chemical Engineering Science, 2001, 56, (21-22), pp. 6217-6224; Liao, et al., “Kinetics of absorption of carbon dioxide into aqueous solutions of monoethanolamine plus N-methyldiethanolamine,” Chemical Engineering Science, 2002, 57, (21), pp. 4569-4582; Ramachandran, et al., “Kinetics of the absorption of CO2 into mixed aqueous loaded solutions of monoethanolamine and methyldiethanolamine,” Industrial & Engineering Chemistry Research, 2006, 45, (8), pp. 2608-2616, each of which is hereby incorporated by reference as if fully set forth herein.
There is a need for an improved apparatus, process and sorbent.